thinkrun: Skill for Claude Code

Before / After

One job: a reviewer opens the PR and sees, side by side, what the surface looked like before the change and after it. Same page, same viewport, same element. Two images and one line of what changed. Nothing else.

This is not proof that the change works — that is prove-it, and the two share captures: if prove-it already produced PNGs, reuse them.

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Inputs

• What to capture: a URL, optionally narrowed to a selector (--selector) for a component-level shot, or --full-page for the whole page.
• Before source (one of): the base revision running somewhere; a previous deployment URL; an existing PNG.
• After source: the change under test, running; or an existing PNG.
• PR number (optional): where the table goes.

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Step 0 — Doctor, mode, target

Already have both PNGs? Skip to "Reusing existing PNGs" at the end — no browser, no doctor, no session. Everything in Steps 0–2 exists to produce the two images.

thinkrun doctor

Local mode for anything behind login or on localhost; cloud mode for public URLs with no display (cloud browsers cannot reach your localhost). (Cloud path: command surface verified against CLI 0.1.37; not smoke-tested when this skill shipped — a session-provisioning incident on 2026-09-18.)

Run exactly one of the two blocks.

Local (behind login, or localhost):

# open your OWN window. A capture needs the tab visible; on a shared machine another
# agent's window can be in front, and Chrome returns "image readback failed" for a hidden tab.
TAB_ID=$(thinkrun new-window "about:blank" --json | jq -er .data.tabId) || exit 1; T="--tab $TAB_ID"
visible() { [ "$(thinkrun evaluate 'document.visibilityState' $T --json | jq -r .data)" = "visible" ] || { echo "tab is hidden; bring the window forward and retake"; exit 1; }; }
same_session() { :; }

Cloud (public URL, no display):

SID=$(thinkrun cloud start --json | jq -er .data.sessionId) || exit 1; T="--mode cloud"
trap 'thinkrun cloud stop -s "$SID" >/dev/null 2>&1' EXIT      # stops THIS session, never whatever is active
# the active cloud session is machine-wide state; there is no per-command session flag,
# so assert it before every navigate and capture:
same_session() { [ "$(thinkrun cloud status --json | jq -r .data.sessionId)" = "$SID" ] || { echo "active cloud session changed; stop"; exit 1; }; }
visible() { [ "$(thinkrun evaluate 'document.visibilityState' $T --json | jq -r .data)" = "visible" ] || { echo "tab is hidden; retake"; exit 1; }; }